This invention relates generally to a circuit protector and, more particularly, to SMD and through-hole fuses and methods of manufacturing SMD and through-hole fuses. In particular, the present invention may be used in connection with all standard sizes of surface mountable devices and through-hole fuses including, but not limited to, 1206, 0805, 0603 and 0402 fuses, as well as with all non-standard fuse sizes. U.S. application Ser. No. 11/091,665, entitled, “Hybrid Chip Fuse Assembly Having Wire Leads And Fabrication Method”, which was published on Sep. 28, 2006 as U.S. Publication No. 20060214259, relates to through-hole fuses and is incorporated by reference herein.
Subminiature circuit protectors are useful in applications in which size and space limitations are important, for example, on circuit boards for electronic equipment, for denser packing and miniaturization of electronic circuits.
Ceramic chip type fuses are typically manufactured by depositing an element layer on a ceramic or glass substrate plate, screen printing the element layer, printing the element layer to a predetermined thickness and width to obtain a certain resistance, attaching an insulating cover over the element layer, and cutting, or dicing, individual fuses from the finished structure. The element layer loses definition when the screen printing operation is performed. The screen printing operation is not very accurate and the edge acuity of the resulting element layer is not very good. Photolithography etching may be used as an alternative to the screen printing operation, but this process is relatively expensive due to additional required processing steps and the longer lead times.
There is a need for a method of manufacturing a subminiature circuit protector that is simple and relatively inexpensive. Additionally, there is also a need for a method of manufacturing a subminiature circuit protector, wherein the element layer may be designed to a certain geometry and also has a fine edge acuity.